“Why not?”
“Well, it depends on the weather and specially the wind. I used to drive and I know something about it. If there’s a wind blowing into the radiator it’ll cool about twice as quickly as if the same wind was blowing from behind the car.”
“I can understand that,” French admitted. “How was the wind that night?”
“A very faint westerly breeze—scarcely noticeable.”
“That would be behind the car. Then if we try it to-day in any pretty sheltered place we ought to get, roughly speaking, the same result? The temperature’s about the same to-day as it was that night, I should think?”
“That’s so, sir, the weather conditions are as good for a test as you’ll get. But even so, it will be only a rough guide.”
“We’ll try it, anyway. Park somewhere and we’ll go and have some lunch.”
They left the car in front of the fine old parish church while they lunched and explored the town. Then returning to the car, they sat down to wait. At intervals they felt the radiator, until, just three and a half hours after their arrival, the last sensation of warmth vanished.
“That’s three hours and thirty minutes,” Daw declared, “but I don’t think you would be wise to take that too literally. If you say something between three and four hours you won’t be far wrong.”
“I agree, Sergeant. That’s all we want. Let’s get home.”